The ability to turn on/off various layers present on an Adobe Workfront file aka the uploaded PDF. While reviewing a document it would be invaluable to be able to turn on various layers in Workfront, those layers can indicate PMS colors, special effects, etc.
A simple layers palette similar to Acrobat would be the easiest and most direct solution as users would be most familiar with that approach.
Currently there is no layer access in Adobe Workfront.